(1 ). Field of the Invention
This invention relates to an apparatus for treating the surface of a thin planar substrate such as semiconductor substrate with a vaporized surface treatment agent. More specifically, this invention relates to an apparatus for treating the surface of a substrate with an adhesion-enhancing agent such as organochlorosilane or hexamethyldisilazane in order to improve the adhesion of a photoresist thereto.
(2). Description of the Prior Art
In order to avoid poor adhesion of a photoresist to the surface of an oxide material such as silicon dioxide substrate and hence to prevent possible undercutting of the oxide material upon etching, the surface of the oxide material is treated, for example, with an adhesion-enhancing agent containing a hexaalkyldisilazane as disclosed in Japanese Patent Publication No. 26043/1972. Upon effecting the surface treatment, the application of the adhesion-enhancing agent to surface of the substrate is conducted, for example, by the spraying method or the spinning method, by dipping the substrate in a solution of the adhesion-enhancing agent, or by placing the substrate in an atmosphere of the adhesion-enhancing agent in a vaporized state.
On the other hand, as disclosed in Japanese Patent Laid-Open No. 31151/1982, there is also known an apparatus for causing a number of semiconductor substrates to pass continuously through a bathing apparatus which contains a vaporized surface improver such as organochlorosilane or hexamethyldisilazane.
As illustrated in FIG. 3 of the accompanying drawings, another apparatus is also known to apply a surface treatment agent to substrates. In FIG. 3, a closed chamber 6 is formed surrounding a substrate 1 supported on a supporting die 2 by means of a cover 3 equipped with a feed pipe 4 for a vaporized surface treatment agent. The vaporized surface treatment agent is fed through the feed pipe 4 into the closed chamber 6. Numeral 3' indicates a packing.
Incidentally, the present assignee has already filed an application for the registration of a utility model on a drying and treatment apparatus similar to the apparatus depicted in FIG. 3, to which Japanese Utility Model Application No. 198947/198947 has been allotted.
Turning back to the conventional apparatus shown in FIG. 3, the supporting die 2 includes unillustrated heating or cooling means and a temperature sensor, which are both housed within the supporting die 2, and also defines vacuum suction holes 5 bored therethrough.
The substrate 1 is mounted on the supporting die 2. While sucking the substrate 1 under vacuum and hence holding it firmly on the upper surface of the supporting die 2, a vaporized surface treatment agent is fed into the closed chamber 6 to treat the surface of the substrate 1 with the surface treatment agent. The conventional apparatus is however accompanied by a problem that the vaporized surface treatment agent, which has been supplied through the feed pipe 4 into the closed chamber 6, is not allowed to adhere uniformly on the surface of the substrate 1.
It also includes another drawback that when an upper cover 3 is kept in contact with the supporting die 2 along the entire periphery of the upper cover 3, conduction of heat takes place at the contacted area and the surface temperature of the supporting die 2 is rendered different from one point to another.
In the conventional apparatus depicted in FIG. 3, the surface treatment agent may be fed into the chamber 6 through the left side wall of the cover 3 and may then be discharged through the right side wall of the cover 3 as viewed on the drawing. Even if the surface treatment agent is fed in the above-described manner, it is either impossible or extremely difficult to achieve uniform adhesion or deposition of the surface treatment agent.